The 23-year-old, who posed for photographs and signed autographs outside the Etihad Stadium on Wednesday, is set to sign a reported five-year contract worth ?£200,000 a week to finalise his move from Atletico Madrid.
After a day of talks at the Etihad Stadium, Aguero retreated to a city centre hotel and then announced on Twitter that the deal was done. "I'm already a City player. Happy to be in this club and this city. Thank you all for the welcome and the reception!" he wrote, although minor details of the deal were still to be completed.
His transfer is believed to be costing City in the region of ?£35million, which was the amount of the buy-out clause written into the contract he only signed with the Spanish side in January.
On Wednesday Aguero, the son-in-law of Argentina icon Diego Maradona, appeared to take everything in his stride after flying in from Buenos Aires via Heathrow. After touching down in the north-west, Aguero wrote on Twitter: "Just arrived in Manchester to finalise the details of signing with City.
"Everything is going very well! I`ll tell you more in a while."
Aguero had a medical at a private Manchester hospital and briefly stopped off at the Etihad Stadium before going out again for lunch and returning in the early evening for further discussion.
City's previous record buy was Robinho, who arrived from Real Madrid for ?£32.5million as new owner Sheikh Mansour, a member of Abu Dhabi's ruling family, made a marquee signing to signal his intent just days after taking over in August 2008.
Source: PA
Source: PA